A new nondegradative method for the isolation of elastin from the lung will be used to study the quantity of elastic tissue in the lungs from subjects of various ages including several subjects who have died as a result of chronic obstructive pulmonary disease with emphysema secondary to an inherited deficiency of alpha-l antitrypsin. These analyses will be confirmed also by a technique that has been devised for the measurement of tissue elastin content from measurements of the unique crosslinking amino acids in elastin, desmosine and isodesmosine. A recently devised radioimmuunoassay for human leukocyte elastase will be used to measure the enzyme in a variety of situations including macrophage culture fluid, fluid obtained from human bronchial lavage, homogenates of human lung tissue obtained at surgery, and blood from normal individuals, individuals with emphysema, and individuals with elevated leukocyte counts. We plan to analyze the lungs of the blotchy mouse for elastin. These animals are remarkable for the presence of emphysema at birth and also have a deficiency of lysyl oxidase. We plan to study the lysyl oxidase content of fibroblasts obtained from the blotchy mouse and maintained in tissue culture. We plan to study the metabolism of desmosine and isodesmosine and investigate the release of elastase from macrophages in tissue culture.